i would start by grouping them into sections because they’re all like terms.
(-7c2-c2) = -8c2
(-5c2-2c2)= -7c2
(8c2-9c2) =-c2
then add them all together.
-8c2-7c2-c2
since they’re all negative you can add them together but don’t forget the negative.
8+7=15
15+1 = 16
add the negative back in to get -16c2
